Motor Vehicle

Abstract

A motor vehicle 5 is disclosed having an engine 10 used to drive a number of ancillary devices 12, 14, 16 and 18 via an ancillary drive 11 . An electronically controlled disengageable connection 21 is provided to selectively disengage the drive from the engine 10 to the ancillary drive 11 when a high power output is required from the engine 10 to drive the motor vehicle 5 . When the ancillary drive 11 is disengaged a source of motive power 12 is used to power the ancillary devices 14, 16 and 18 so as to maintain their operation.

1 . A motor vehicle having an internal combustion engine, an ancillary drive to driveably connect one or more ancillary devices to an output from the engine, a disengageable connection interposed between the output from the engine and the ancillary drive to permit the ancillary drive to be disengagaged from the engine, and a controller to control the disengageable connection, wherein when at least one vehicle operating condition indicating that a high power output is required from the engine is present, the disengageable connection is disengaged and a source of motive power driveably connected to the ancillary drive is energised to drive the one or more ancillary devices. 
   
   
       2 . A motor vehicle as claimed in  claim 1  wherein the disengageable connection is a clutch controlled by the controller. 
   
   
       3 . A motor vehicle as claimed in  claim 1  wherein the source of motive power is one of an electric machine, a hydraulic motor and a steam powered motor. 
   
   
       4 . A motor vehicle as claimed in  claim 1  wherein the source of motive power is an electric machine forming one of the one or more ancillary devices driveably connected to the engine by the ancillary drive. 
   
   
       5 . A motor vehicle as claimed in  claim 4  wherein the electric machine is a motor/generator used to start the engine. 
   
   
       6 . A motor vehicle as claimed in  claim 1  wherein the one or more ancillary devices comprises at least one of a power assisted steering pump, an air-conditioning compressor, an engine coolant pump and an electrical generator. 
   
   
       7 . A motor vehicle as claimed in  claim 1  wherein the vehicle operating condition is one of an input from an accelerator pedal indicating that a high power output is demanded, a signal from a driver operated switch used to request a high power output from the engine and an indication that the motor vehicle is unable to maintain the current forward speed even though an accelerator pedal is fully depressed. 
   
   
       8 . A motor vehicle as claimed in  claim 1  wherein the output from the engine is a crankshaft of the engine. 
   
   
       9 . A motor vehicle as claimed in  claims 1  wherein the controller is part of a control system used to control operation of the engine and to energise the source of motive power.